Method and apparatus for enhanced electrolytic detachment

Abstract

A method and assembly for forming an occlusion within a vascular cavity. The assembly includes a catheter having an elongate shaft comprising a metallic tubular member extending from a proximal portion to a distal portion of the catheter, a delivery wire including an occlusion member detachably coupled thereto, and a power supply for providing an electrical current to initiate electrolysis at a sacrificial link between the delivery wire and the occlusion member in order to decouple the occlusion member from the delivery wire. The invention also includes a method of positioning and disposing an occlusion member within a vascular cavity using electrolysis, wherein a distal portion of the metallic tubular member serves as a first electrode and the sacrificial link serves as a second electrode. Thus, both the first electrode and the second electrode may be intravenously located proximate a vascular cavity.

1 . A method of forming an occlusion within a vascular cavity in a vasculature of a body of a patient, the method comprising: 
 providing a catheter including a metallic tubular member having a proximal portion and a distal portion;    advancing the catheter through the vasculature such that the distal portion of the metallic tubular member is proximate the vascular cavity and the proximal portion of the metallic tubular member is external the body;    providing an elongate metallic delivery wire having a proximal portion and a distal portion, and an occlusion member detachably coupled to the distal portion of the delivery wire at a sacrificial link;    advancing the occlusion member and delivery wire through the catheter;    positioning the occlusion member within the vascular cavity such that the distal portion of the metallic tubular member is proximate the sacrificial link;    coupling a power source to the proximal portion of the metallic tubular member and the proximal portion of the delivery wire; and    applying an electrical current through the delivery wire and the metallic tubular member to electrolytically dissipate the sacrificial link such that the occlusion member is decoupled from the delivery wire, wherein a first electrode includes the distal portion of the metallic tubular member and a second electrode includes the sacrificial link.    
     
     
         2 . The method of  claim 1 , wherein the first electrode is a cathode and the second electrode is an anode.  
     
     
         3 . The method of  claim 1 , wherein the distal portion of the metallic tubular member is in electrical communication with an electrically conductive fluid within the body.  
     
     
         4 . The method of  claim 1 , wherein the metallic tubular member includes an outer surface, and wherein at least a portion of the outer surface is in electrical communication with an electrically conductive fluid within the body.  
     
     
         5 . The method of  claim 1 , wherein the metallic tubular member includes an inner surface, and wherein at least a portion of the inner surface is in electrical communication with an electrically conductive fluid within the body.  
     
     
         6 . The method of  claim 1 , wherein the distal portion of the metallic tubular member is positioned within 20 cm or less of the sacrificial link.  
     
     
         7 . The method of  claim 1 , wherein the distal portion of the metallic tubular member is positioned within 5 cm or less of the sacrificial link.  
     
     
         8 . The method of  claim 1 , wherein the distal portion of the metallic tubular member is positioned within 1 cm or less of the sacrificial link.  
     
     
         9 . The method of  claim 1 , wherein the catheter is advanced through the vasculature greater than 20 cm.  
     
     
         10 . The method of  claim 1 , wherein the catheter is advanced through the vasculature greater than 50 cm.  
     
     
         11 . The method of  claim 1 , wherein a distal end of the catheter abuts, mates with, or extends through an opening of the vascular cavity.  
     
     
         12 . A method of depositing of a coil within an intracranial aneurysm in a vasculature of a body of a patient, the method comprising: 
 providing a microcatheter including a metallic tubular member having a proximal portion and a distal portion;    advancing the microcatheter through the vasculature such that the distal portion of the metallic tubular member is proximate the intracranial aneurysm and the proximal portion of the metallic tubular member is external the body;    providing an elongate metallic delivery wire having a proximal portion and a distal portion, and a coil detachably coupled to the distal portion of the delivery wire at a sacrificial link;    advancing the coil and delivery wire through the microcatheter;    positioning the coil within the intracranial aneurysm such that the distal portion of the metallic tubular member is proximate the sacrificial link;    coupling a power source to the proximal portion of the metallic tubular member and the proximal portion of the delivery wire; and    applying an electrical current through the delivery wire and the metallic tubular member to electrolytically dissipate the sacrificial link such that the coil is decoupled from the delivery wire, wherein a first electrode includes the distal portion of the metallic tubular member and a second electrode includes the sacrificial link.    
     
     
         13 . The method of  claim 12 , wherein the first electrode is a cathode and the second electrode is an anode.  
     
     
         14 . The method of  claim 12 , wherein the distal portion of the metallic tubular member is in electrical communication with a bloodstream.  
     
     
         15 . The method of  claim 12 , wherein the distal portion of the metallic tubular member is positioned within 10 cm or less of the sacrificial link.  
     
     
         16 . The method of  claim 12 , wherein the distal portion of the metallic tubular member is positioned within 5 cm or less of the sacrificial link.  
     
     
         17 . A method of forming an occlusion within a vascular cavity, the method comprising: 
 providing a catheter having a proximal end, a distal end, a length and a lumen extending therethrough, the catheter including a metallic tubular member extending a majority of the length of the catheter, the metallic tubular member having a proximal portion and a distal portion;    advancing the catheter through a vasculature such that the distal end of the catheter is proximate the vascular cavity;    providing an elongate metallic delivery wire having a proximal portion and a distal portion, and an occlusion member detachably coupled to the distal portion of the delivery wire;    advancing the occlusion member and delivery wire through the lumen of the catheter to the vascular cavity;    positioning the occlusion member within the vascular cavity, such that the distal portion of the metallic tubular member is proximate the occlusion member;    coupling an electrical power source to the proximal portion of the metallic tubular member and the proximal portion of the delivery wire; and    applying an electrical current through the delivery wire and the metallic tubular member to electrolytically decouple the occlusion member from the delivery wire, wherein a first electrode includes the distal portion of the metallic tubular member and a second electrode includes the distal portion of the delivery wire.    
     
     
         18 . The method of  claim 17 , wherein the occlusion member extends distal of the distal portion of the delivery wire.  
     
     
         19 . The method of  claim 17 , wherein the first electrode is a cathode and the second electrode is an anode.  
     
     
         20 . The method of  claim 17 , wherein the distal portion of the metallic tubular member is an exposed distal portion.  
     
     
         21 . The method of  claim 17 , wherein the distance between the distal portion of the metallic tubular member and the occlusion member when the occlusion member is positioned within the vascular cavity is less than 50 cm.  
     
     
         22 . The method of  claim 17 , wherein the distance between the distal portion of the metallic tubular member and the occlusion member when the occlusion member is positioned within the vascular cavity is less than 20 cm.  
     
     
         23 . The method of  claim 17 , wherein the distance between the distal portion of the metallic tubular member and the occlusion member when the occlusion member is positioned within the vascular cavity is less than 5 cm.  
     
     
         24 . The method of  claim 17 , wherein the distance between the distal portion of the metallic tubular member and the occlusion member when the occlusion member is positioned within the vascular cavity is less than 1 cm.  
     
     
         25 . The method of  claim 17 , wherein the catheter is advanced through the vasculature greater than 20 cm.  
     
     
         26 . The method of  claim 17 , wherein the catheter is advanced through the vasculature greater than 50 cm.  
     
     
         27 . The method of  claim 17 , wherein the distal end of the catheter abuts, mates with, or extends through an opening of the vascular cavity.  
     
     
         28 . An assembly for electrolytically disposing a coil in a vascular cavity, the assembly comprising: 
 a cathode comprising an exposed distal portion of a metallic tubular member, the metallic tubular member extending from a proximal portion to a distal portion of a catheter and defining a catheter lumen, the metallic tubular member providing an electrically conductive pathway during use;    an anode comprising a sacrificial link between a metallic delivery wire and a coil, the delivery wire providing an electrically conductive pathway during use;    wherein the delivery wire is positioned in the catheter lumen such that the anode is proximate the cathode during use in a vascular region; and    a current source coupled to a proximal portion of the metallic tubular member and a proximal portion of the delivery wire, wherein during use the current source provides an electrolytic current through the assembly to dissipate the sacrificial link such that the coil is decoupled from the delivery wire.    
     
     
         29 . The assembly of  claim 28 , wherein during use the anode is positioned less than 20 cm from the cathode.  
     
     
         30 . The assembly of  claim 28 , wherein during use the anode is positioned less than 5 cm from the cathode.  
     
     
         31 . The assembly of  claim 28 , wherein the metallic tubular member comprises a plurality of slots and beams.  
     
     
         32 . An assembly for forming an occlusion in a vascular cavity, the assembly comprising: 
 a catheter having a proximal end, a distal end, a length and a lumen extending therethrough, the catheter including a metallic tubular member extending a majority of the length of the catheter, the metallic tubular member having a proximal portion and a distal portion, wherein the metallic tubular member provides an electrically conductive pathway during use;    an elongate metallic delivery wire having a proximal portion and a distal portion, wherein the delivery wire provides an electrically conductive pathway during use;    an occlusion member detachably coupled to the distal portion of the delivery wire at a sacrificial link;    wherein during use the delivery wire is disposed through the lumen of the catheter such that the distal portion of the delivery wire is proximate the distal portion of the metallic tubular member when the occlusion member is positioned within the vascular cavity;    a current source coupled to the proximal portion of the metallic tubular member and the proximal portion of the delivery wire, wherein the current source provides an electrolytic current through the metallic tubular member and the delivery wire to initiate electrolysis at the sacrificial link; and    wherein the distal portion of the metallic tubular member serves as a cathode and the sacrificial link serves as an anode during electrolysis.    
     
     
         33 . The assembly of  claim 32 , wherein the length of the catheter is greater than 20 cm.  
     
     
         34 . The assembly of  claim 32 , wherein the length of the catheter is greater than 50 cm.  
     
     
         35 . The assembly of  claim 32 , wherein the length of the catheter is greater than 100 cm.  
     
     
         36 . The assembly of  claim 32 , wherein the occlusion member is a coil.  
     
     
         37 . The assembly of  claim 32 , wherein the occlusion member comprises platinum.  
     
     
         38 . The assembly of  claim 32 , wherein the delivery wire comprises stainless steel.  
     
     
         39 . The assembly of  claim 32 , wherein the metallic tubular member comprises stainless steel, a stainless steel alloy, or a nickel-titanium alloy.  
     
     
         40 . The assembly of  claim 32 , wherein the current source includes a direct current source having a positive terminal and a negative terminal, wherein the positive terminal is connected to the delivery wire and the negative terminal is connected to the metallic tubular member of the catheter.  
     
     
         41 . The assembly of  claim 32 , wherein the metallic tubular member has an outer surface, and wherein at least a portion of the outer surface is in electrical communication with an electrically conductive fluid within the body.  
     
     
         42 . The assembly of  claim 32 , wherein the metallic tubular member has an inner surface, and wherein at least a portion of the inner surface is in electrical communication with an electrically conductive fluid within the body.  
     
     
         43 . The assembly of  claim 32 , wherein the metallic tubular member comprises a plurality of slots and beams.  
     
     
         44 . A kit for depositing a coil within an aneurysm in a vasculature of a body of a patient, the kit comprising: 
 a catheter having a proximal end, a distal end, a length and a lumen extending therethrough, the catheter including a metallic tubular member extending a majority of the length of the catheter, the metallic tubular member having a proximal portion and a distal portion, wherein the distal portion acts as a cathode during use;    an elongate metallic delivery wire having a proximal portion and a distal portion;    a coil detachably coupled to the distal portion of the delivery wire at a sacrificial link, wherein the sacrificial link acts as an anode during use; and    a power supply coupled to the proximal portion of the metallic delivery wire and the proximal portion of the metallic tubular member;    wherein the kit forms an intravascular electrolytic cell during use.    
     
     
         45 . The kit of  claim 44 , wherein the catheter has a length greater than 20 cm  
     
     
         46 . The kit of  claim 44 , wherein the catheter has a length greater than 50 cm.  
     
     
         47 . The kit of  claim 44 , wherein the catheter has a length greater than 100 cm.  
     
     
         48 . The kit of  claim 44 , wherein the power supply is a direct current power supply having a positive terminal and a negative terminal, and wherein the positive terminal is coupled to the metallic delivery wire and the negative terminal is coupled to the metallic tubular member.  
     
     
         49 . The kit of  claim 44 , wherein the metallic tubular member includes a plurality of slots and beams.  
     
     
         50 . An electrolytic cell of a medical device assembly, the electrolytic cell comprising: 
 a cathode comprising a distal portion of a metallic tubular member exposed to a bloodstream, the metallic tubular member extending from a proximal portion to a distal portion of a catheter and defining a catheter lumen, the metallic tubular member providing an electrically conductive pathway during use;    an anode comprising a sacrificial link exposed to a bloodstream, the sacrificial link joining a metallic delivery wire and a coil, the delivery wire providing an electrically conductive pathway during use;    wherein the delivery wire is positioned in the catheter lumen such that the anode is proximate the cathode; and    a current source coupled to a proximal portion of the metallic tubular member and a proximal portion of the delivery wire.